The short version
Nonthaburi is a river province and a city in its own right, not simply Bangkok’s cheaper northern edge. The Chao Phraya, old temples, civic offices and dense roads give it a more provincial cadence than central Bangkok. It suits someone whose work is north or west of the centre, or who wants more space and a less visitor dominated daily life.
Choosing the river corridor
The Purple Line corridor around Phra Nang Klao Bridge, Nonthaburi Civic Center and Yaek Tiwanon is the most legible base. The river side is older and more atmospheric, with piers, markets and temples, while Rattanathibet is a broad modern road lined with shopping and apartment development. The distance between them is deceptively large on foot.
Getting around
The Purple Line connects Nonthaburi with Bang Yai and Tao Poon, where the Blue Line continues into Bangkok. Buses, river boats and motorbike taxis remain important. Near a station, car free living is plausible. Elsewhere, a car makes family errands easier but puts you at the mercy of Rattanathibet traffic.
My verdict
Nonthaburi is a strong choice for an independent household that does not need to be in Sukhumvit every night. It is weaker for a first arrival who wants instant familiarity with central Bangkok. Learn the river side and the road side separately before deciding.